Search

The aim of the present survey was to analyze plasma vitamin B6 levels in post-bariatric patients and to elucidate the causal factors associated with elevated plasma vitamin B6 levels. This is a retrospective analysis of electronic patient data of all post-bariatric patients evaluated at the endocrine outpatient clinic of the University Hospital Basel in 2017, for which plasma vitamin B6 values were assessed during regular follow-up visits. In total, 205 patients were included in the study, whereof a minority of 43% had vitamin B6 levels in the normal range. 50% of the patients had vitamin B6 levels up to fourfold higher than the upper normal limit and 7% had levels more than fourfold above the upper normal limit. Vitamin B6 deficiency was not observed in any patient. While multivitamin supplementation in general was associated with elevated plasma vitamin B6 levels, the highest vitamin B6 levels were found after biliopancreatic diversion (BPD) and in patients who reported daily energy drink intake. Elevated plasma vitamin B6 levels up to fourfold above the upper normal limit are common in postbariatric patients and are associated with regular multivitamin supplementation, while highly elevated plasma vitamin B6 levels were seen primarily upon regular energy drink intake. Thus, a regular follow-up of vitamin B6 plasma levels and critical evaluation of vitamin B6 supplementation, either as part of the multivitamin preparation or related to regular energy drink intake, is highly warranted and should be an integral part of the routine post-bariatric follow-up.

Human obesity is associated with decreased circulating adiponectin and elevated leptin levels. In vitro experiments and studies in high fat diet (HFD)-fed mice suggest that interleukin-6 (IL-6) may regulate adiponectin and leptin release from white adipose tissue (WAT). Herein, we aimed to investigate whether IL-6 receptor blockade affects the levels of circulating adiponectin and leptin in obese human individuals. To this end, serum samples collected during a multicenter, double-blind clinical trial were analyzed. In the latter study, obese human subjects with or without type 2 diabetes were randomly assigned to recurrent placebo or intravenous tocilizumab (an IL-6 receptor antibody) administration during a 12-week exercise training intervention. Twelve weeks of tocilizumab administration (in combination with exercise training) trend wise enhanced the decrease in circulating leptin levels (−2.7 ± 8.2% in the placebo vs. −20.6 ± 5.6% in tocilizumab, p = 0.08) and significantly enhanced the increase in circulating adiponectin (3.4 ± 3.7% in the placebo vs. 27.0 ± 6.6% in tocilizumab, p = 0.01). In addition, circulating adiponectin levels were negatively correlated with the homeostatic model assessment of insulin resistance (HOMA-IR), indicating that increased adiponectin levels positively affect insulin sensitivity in people with obesity. In conclusion, IL-6 receptor blockade increases circulating adiponectin levels in people with obesity.

Summary: Mitochondrial oxidative phosphorylation (OXPHOS) and substrate utilization critically regulate the function of hypothalamic proopiomelanocortin (POMC)-expressing neurons. Here, we demonstrate that inactivation of apoptosis-inducing factor (AIF) in POMC neurons mildly impairs mitochondrial respiration and decreases firing of POMC neurons in lean mice. In contrast, under diet-induced obese conditions, POMC-Cre-specific inactivation of AIF prevents obesity-induced silencing of POMC neurons, translating into improved glucose metabolism, improved leptin, and insulin sensitivity, as well as increased energy expenditure in AIFΔPOMC mice. On a cellular level, AIF deficiency improves mitochondrial morphology, facilitates the utilization of fatty acids for mitochondrial respiration, and increases reactive oxygen species (ROS) formation in POMC neurons from obese mice, ultimately leading to restored POMC firing upon HFD feeding. Collectively, partial impairment of mitochondrial function shifts substrate utilization of POMC neurons from glucose to fatty acid metabolism and restores their firing properties, resulting in improved systemic glucose and energy metabolism in obesity. : Timper et al. show that mild impairment of mitochondrial OXPHOS upon deletion of AIF or MPC1 in hypothalamic POMC-expressing neurons increases their fatty acid utilization and ROS formation, prevents obesity-induced silencing of these neurons, and improves systemic glucose metabolism in obesity. Keywords: hypothalamic POMC-neurons, apoptosis-inducing factor, AIF, mitochondrial, pyruvate carrier-1, MPC-1, mitochondrial oxidative phosphorylation, fatty acid, oxidation, reactive oxygen species, ROS, obesity

Objectives Cytokines such as IL-1 seems to play a role in the pathogenesis of fatigue associated with some chronic diseases and anti-inflammatory treatment has been shown to reduce these symptoms. Ingestion of a calorie rich meal leads to postprandial fatigue, and is associated with increased systemic concentrations of cytokines, which is more pronounced in obese than lean subjects. We investigated whether postprandial fatigue is regulated by IL-1, and therefore reduced by IL-1 antagonism, in lean and obese subjects. Methods In a double-blind, crossover study in 8 lean and 8 obese male subjects, randomized to receive either saline (placebo) or the IL-1 receptor antagonist anakinra, we investigated whether postprandial fatigue was regulated by IL-1. To promote postprandial fatigue, subjects ran 30 min prior to a high-fat, high-carbohydrate meal. Fatigue was determined using the Stanford Sleepiness Scale and blood samples were drawn at baseline and after the intervention. Results IL-1 antagonism led to a reduction in postprandial fatigue and this effect was more pronounced in obese than lean individuals. Conclusions We conclude that IL-1 is involved in the regulation of postprandial fatigue under physiologic conditions in lean and obese individuals. It remains to be shown whether this effect translates into clinical relevant effects., Graphical abstract, Highlights • Ingestion of a calorie rich meal leads to postprandial fatigue • IL-1 contributes to postprandial fatigue in lean and obese individuals. • IL-1 antagonism may decrease postprandial fatigue in humans.

The ‘obesity epidemic’ represents a major global socioeconomic burden that urgently calls for a better understanding of the underlying causes of increased weight gain and its associated metabolic comorbidities, such as type 2 diabetes mellitus and cardiovascular diseases. Improving our understanding of the cellular basis of obesity could set the stage for the development of new therapeutic strategies. The CNS plays a pivotal role in the regulation of energy and glucose homeostasis. Distinct neuronal cell populations, particularly within the arcuate nucleus of the hypothalamus, sense the nutrient status of the organism and integrate signals from peripheral hormones including pancreas-derived insulin and adipocyte-derived leptin to regulate calorie intake, glucose metabolism and energy expenditure. The arcuate neurons are tightly connected to other specialized neuronal subpopulations within the hypothalamus, but also to various extrahypothalamic brain regions, allowing a coordinated behavioral response. This At a Glance article gives an overview of the recent knowledge, mainly derived from rodent models, regarding the CNS-dependent regulation of energy and glucose homeostasis, and illustrates how dysregulation of the neuronal networks involved can lead to overnutrition and obesity. The potential impact of recent research findings in the field on therapeutic treatment strategies for human obesity is also discussed., Summary: This at a glance article gives an overview of the recent knowledge mainly derived from rodent models regarding the CNS-dependent regulation of energy and glucose homeostasis, and depicts how dysregulation of the involved neuronal networks promotes overnutrition and obesity.

Summary: Interleukin (IL)-6 engages similar signaling mechanisms to leptin. Here, we find that central application of IL-6 in mice suppresses feeding and improves glucose tolerance. In contrast to leptin, whose action is attenuated in obesity, the ability of IL-6 to suppress feeding is enhanced in obese mice. IL-6 suppresses feeding in the absence of neuronal IL-6-receptor (IL-6R) expression in hypothalamic or all forebrain neurons of mice. Conversely, obese mice exhibit increased soluble IL-6R levels in the cerebrospinal fluid. Blocking IL-6 trans-signaling in the CNS abrogates the ability of IL-6 to suppress feeding. Furthermore, gp130 expression is enhanced in the paraventricular nucleus of the hypothalamus (PVH) of obese mice, and deletion of gp130 in the PVH attenuates the beneficial central IL-6 effects on metabolism. Collectively, these experiments indicate that IL-6 trans-signaling is enhanced in the CNS of obese mice, allowing IL-6 to exert its beneficial metabolic effects even under conditions of leptin resistance. : Timper et al. find that central IL-6 improves energy and glucose homeostasis via IL-6 trans-signaling. IL-6 trans-signaling is enhanced in the CNS of obese mice, allowing IL-6 to exert its beneficial metabolic effects even under conditions of leptin resistance. Keywords: interleukin-6, CNS, obesity, interleukin-6 trans-signaling, energy homeostasis, glucose homeostasis

IL-6 is a cytokine with various effects on metabolism. In mice, IL-6 improved beta cell function and glucose homeostasis via upregulation of glucagon-like peptide 1 (GLP-1), and IL-6 release from muscle during exercise potentiated this beneficial increase in GLP-1. This study aimed to identify whether exercise-induced IL-6 has a similar effect in humans. In a multicentre, double-blind clinical trial, we randomly assigned patients with type 2 diabetes or obesity to intravenous tocilizumab (an IL-6 receptor antagonist) 8 mg/kg every 4 weeks, oral sitagliptin (a dipeptidyl peptidase-4 inhibitor) 100 mg daily or double placebos (a placebo saline infusion every 4 weeks and a placebo pill once daily) during a 12 week training intervention. The primary endpoints were the difference in change of active GLP-1 response to an acute exercise bout and change in the AUC for the concentration–time curve of active GLP-1 during mixed meal tolerance tests at baseline and after the training intervention. Nineteen patients were allocated to tocilizumab, 17 to sitagliptin and 16 to placebos. During the acute exercise bout active GLP-1 levels were 26% lower with tocilizumab (multiplicative effect: 0.74 [95% CI 0.56, 0.98], p = 0.034) and 53% higher with sitagliptin (1.53 [1.15, 2.03], p = 0.004) compared with placebo. After the 12 week training intervention, the active GLP-1 AUC with sitagliptin was about twofold that with placebo (2.03 [1.56, 2.62]; p

Background & Aims Glucose-dependent insulinotropic peptide (GIP) induces production of interleukin 6 (IL6) by adipocytes. IL6 increases production of glucagon-like peptide (GLP)-1 by L cells and α cells, leading to secretion of insulin from β cells. We investigated whether GIP regulates GLP1 and glycemia via IL6. Methods We obtained samples of human pancreatic islets and isolated islets from mice; human α cells and β cells were sorted by flow cytometry and incubated with GIP. Islets were analyzed by quantitative polymerase chain reaction and immunohistochemistry. BKS.Cg-Dock7m+/+ Leprdb/J db/db mice (diabetic mice) and db/+ mice, as well as C57BL/6J IL6-knockout mice (IL6-KO) and C57BL/6J mice with the full-length Il6 gene (controls), were fed a chow or a high-fat diet; some mice were given injections of recombinant GIP, IL6, GLP, a neutralizing antibody against IL6 (anti-IL6), lipopolysaccharide, and/or IL1B. Mice were given a glucose challenge and blood samples were collected and analyzed. Results Incubation of mouse and human pancreatic α cells with GIP induced their production of IL6, leading to production of GLP1 and insulin secretion from pancreatic islets. This did not occur in islets from IL6-KO mice or in islets incubated with anti-IL6. Incubation of islets with IL1B resulted in IL6 production but directly reduced GLP1 production. Incubation of mouse islets with the sodium glucose transporter 2 inhibitor dapagliflozin induced production of GLP1 and IL6. Injection of control mice with GIP increased plasma levels of GLP1, insulin, and glucose tolerance; these effects were amplified in mice given lipopolysaccharide but reduced in IL6-KO mice or in mice given anti-IL6. Islets from diabetic mice had increased levels of IL1B and IL6, compared with db/+ mice, but injection of GIP did not lead to production of GLP1 or reduce glycemia. Conclusions In studies of pancreatic islets from human beings and mice, we found that GIP induces production of IL6 by α cells, leading to islet production of GLP1 and insulin. This process is regulated by inflammation, via IL1B, and by sodium glucose transporter 2. In diabetic mice, increased islet levels of IL6 and IL1B might increase or reduce the production of GLP1 and affect glycemia.

Activation of Agouti-related peptide (AgRP) neurons potently promotes feeding, and chronically altering their activity also affects peripheral glucose homeostasis. We demonstrate that acute activation of AgRP neurons causes insulin resistance through impairment of insulin-stimulated glucose uptake into brown adipose tissue (BAT). AgRP neuron activation acutely reprograms gene expression in BAT toward a myogenic signature, including increased expression of myostatin. Interference with myostatin activity improves insulin sensitivity that was impaired by AgRP neurons activation. Optogenetic circuitry mapping reveals that feeding and insulin sensitivity are controlled by both distinct and overlapping projections. Stimulation of AgRP → LHA projections impairs insulin sensitivity and promotes feeding while activation of AgRP → anterior bed nucleus of the stria terminalis (aBNST)vl projections, distinct from AgRP → aBNSTdm projections controlling feeding, mediate the effect of AgRP neuron activation on BAT-myostatin expression and insulin sensitivity. Collectively, our results suggest that AgRP neurons in mice induce not only eating, but also insulin resistance by stimulating expression of muscle-related genes in BAT, revealing a mechanism by which these neurons rapidly coordinate hunger states with glucose homeostasis.

Pathological activation of the renin-angiotensin system (RAS) is associated with the metabolic syndrome, and the new onset of type 2 diabetes can be delayed by RAS inhibition. In animal models of type 2 diabetes, inhibition of the RAS improves insulin secretion. However, the direct effects of angiotensin II on islet function and underlying mechanisms independent of changes in blood pressure remain unclear. Here we show that exposure of human and mouse islets to angiotensin II induces interleukin (IL)-1–dependent expression of IL-6 and MCP-1, enhances β-cell apoptosis, and impairs mitochondrial function and insulin secretion. In vivo, mice fed a high-fat diet and treated with angiotensin II and the vasodilator hydralazine to prevent hypertension showed defective glucose-stimulated insulin secretion and deteriorated glucose tolerance. Application of an anti–IL-1β antibody reduced the deleterious effects of angiotensin II on islet inflammation, restored insulin secretion, and improved glycemia. We conclude that angiotensin II leads to islet dysfunction via induction of inflammation and independent of vasoconstriction. Our findings reveal a novel role for the RAS and an additional rationale for the treatment of type 2 diabetic patients with an IL-1β antagonist.

Summary Skeletal muscle accumulates ceramides in obesity, which contribute to the development of obesity-associated insulin resistance. However, it remained unclear which distinct ceramide species in this organ contributes to instatement of systemic insulin resistance. Here, ceramide profiling of high-fat diet (HFD)-fed animals revealed increased skeletal muscle C18:0 ceramide content, concomitant with increased expression of ceramide synthase (CerS)1. Mice lacking CerS1, either globally or specifically in skeletal muscle (CerS1ΔSkM), exhibit reduced muscle C18:0 ceramide content and significant improvements in systemic glucose homeostasis. CerS1ΔSkM mice exhibit improved insulin-stimulated suppression of hepatic glucose production, and lack of CerS1 in skeletal muscle improves systemic glucose homeostasis via increased release of Fgf21 from skeletal muscle. In contrast, muscle-specific deficiency of C16:0 ceramide-producing CerS5 and CerS6 failed to protect mice from obesity-induced insulin resistance. Collectively, these results reveal the tissue-specific function of distinct ceramide species during the development of obesity-associated insulin resistance.

Obesity-related insulin resistance is linked to a chronic state of systemic and adipose tissue-derived inflammation. Glucose-dependent insulinotropic polypeptide (GIP) is an incretin hormone also acting on adipocytes. We investigated whether GIP affects inflammation, lipolysis, and insulin resistance in human adipocytes. Human subcutaneous preadipocyte-derived adipocytes, differentiated in vitro, were treated with human GIP to analyze mRNA expression and protein secretion of cytokines, glycerol, and free fatty acid release and insulin-induced glucose uptake. GIP induced mRNA expression of IL-6, IL-1β, and the IL-1 receptor antagonist IL-1Ra, whereas TNFα, IL-8, and monocyte chemotactic protein (MCP)-1 remained unchanged. Cytokine induction involved PKA and the NF-κB pathway as well as an autocrine IL-1 effect. Furthermore, GIP potentiated IL-6 and IL-1Ra secretion in the presence of LPS, IL-1β, and TNFα. GIP induced lipolysis via activation of hormone-sensitive lipase and was linked to NF-κB activation. Finally, chronic GIP treatment impaired insulin-induced glucose uptake possibly due to the observed impaired translocation of glucose transporter GLUT4. In conclusion, GIP induces an inflammatory and prolipolytic response via the PKA -NF-κB-IL-1 pathway and impairs insulin sensitivity of glucose uptake in human adipocytes.

Uridine-diphosphate (UDP) and its receptor P2Y6 have recently been identified as regulators of AgRP neurons. UDP promotes feeding via activation of P2Y6 receptors on AgRP neurons, and hypothalamic UDP concentrations are increased in obesity. However, it remained unresolved whether inhibition of P2Y6 signaling pharmacologically, globally, or restricted to AgRP neurons can improve obesity-associated metabolic dysfunctions. Here, we demonstrate that central injection of UDP acutely promotes feeding in diet-induced obese mice and that acute pharmacological blocking of CNS P2Y6 receptors reduces food intake. Importantly, mice with AgRP-neuron-restricted inactivation of P2Y6 exhibit reduced food intake and fat mass as well as improved systemic insulin sensitivity with improved insulin action in liver. Our results reveal that P2Y6 signaling in AgRP neurons is involved in the onset of obesity-associated hyperphagia and systemic insulin resistance. Collectively, these experiments define P2Y6 as a potential target to pharmacologically restrict both feeding and systemic insulin resistance in obesity.

Objectives Patients receiving glucocorticoid treatment are prone to develop metabolic complications. In preclinical studies, metformin prevented the development of the metabolic syndrome during glucocorticoid excess. We herein investigated the metabolic effect of metformin during glucocorticoid treatment in non-diabetic patients. Methods In a double-blind, placebo-controlled trial, patients starting glucocorticoid treatment (prednisone, prednisolone or methylprednisolone) for four weeks were randomised to concomitantly receive metformin (850 mg once daily for one week followed by 850 mg twice daily for three weeks) or placebo. All patients underwent a standardised oral glucose tolerance test at baseline and after four weeks. The primary endpoint was change in the 2-h area under the curve (AUC) of glucose during the oral glucose tolerance test between baseline and four weeks. Results 29 of 34 randomised non-diabetic patients completed the trial (17 metformin and 12 placebo). In patients allocated to placebo, median glucose 2-h AUC increased from baseline to four weeks (836 (IQR 770–966) to 1202 (1009–1271) mmol/L per min; P = 0.01). In contrast, glucose levels remained similar to baseline in the metformin group (936 (869–1003) to 912 (825–1011) mmol/L per min; P = 0.83). This change within four weeks was different between both groups (P = 0.005). Glucocorticoid equivalent doses were similar in both groups (placebo: 980.0 (560.0–3259.8) mg/28 days; metformin: 683.0 (437.5–1970.5) mg/28 days; P = 0.26). Conclusions In this first randomised controlled trial of metformin targeting metabolic complications in patients needing glucocorticoid therapy, we observed a beneficial effect of metformin on glycaemic control. Metformin thus seems to be a promising drug for preventing metabolic side effects during systemic glucocorticoid treatment.

The deleterious effect of chronic activation of the IL-1β system on type 2 diabetes and other metabolic diseases is well documented. However, a possible physiological role for IL-1β in glucose metabolism has remained unexplored. Here we found that feeding induced a physiological increase in the number of peritoneal macrophages that secreted IL-1β, in a glucose-dependent manner. Subsequently, IL-1β contributed to the postprandial stimulation of insulin secretion. Accordingly, lack of endogenous IL-1β signaling in mice during refeeding and obesity diminished the concentration of insulin in plasma. IL-1β and insulin increased the uptake of glucose into macrophages, and insulin reinforced a pro-inflammatory pattern via the insulin receptor, glucose metabolism, production of reactive oxygen species, and secretion of IL-1β mediated by the NLRP3 inflammasome. Postprandial inflammation might be limited by normalization of glycemia, since it was prevented by inhibition of the sodium-glucose cotransporter SGLT2. Our findings identify a physiological role for IL-1β and insulin in the regulation of both metabolism and immunity.

Context: Apelin and arginine vasopressin are antagonists in the regulation of body fluid and osmotic homeostasis. There are no data about apelin levels in patients with polyuria-polydipsia syndrome (PPS). Objective: To investigate plasma apelin levels and plasma apelin to copeptin ratios in patients with PPS and healthy volunteers using copeptin as a surrogate marker for arginine vasopressin. Design, Participants, and Setting: We included 41 patients with PPS in this post hoc analysis of a prospective study performed in tertiary care hospitals in Switzerland and Germany and 113 healthy volunteers as a control group. Outcome Measures: Plasma apelin and copeptin levels were measured in 15 patients with complete central diabetes insipidus (DI), seven patients with complete nephrogenic DI, 19 patients with primary polydipsia (PP), and 113 healthy volunteers. Results: Plasma apelin levels were highest in patients with complete nephrogenic DI (413 pmol/L; interquartile range, 332-504 pmol/L; P = .01) and lower in patients with PP (190 [172-215] pmol/L; P < .001) or complete central DI (209 [174-241] pmol/L; P = .02) as compared to healthy volunteers (254 [225-311] pmol/L). Plasma apelin to copeptin ratio in patients with PP (53 [38-92] pmol/pmol; P > .9) was similar to healthy volunteers (57 [37-102] pmol/pmol). In contrast, the apelin to copeptin ratio was higher in patients with complete central DI (89 [73-135] pmol/pmol; P = .02) and lower in patients with complete nephrogenic DI (7 [6-10] pmol/pmol; P < .001) compared to healthy volunteers. Conclusion: In PP, normal plasma apelin to copeptin ratio attests a normal water homeostasis. In contrast, in patients with central or nephrogenic DI, the increased or decreased apelin to copeptin ratio, respectively, reflects a disturbed osmotic and body fluid homeostasis.

Severe systemic infections induce ubiquitous calcitonin (CALC) gene expression with release of calcitonin peptides, namely procalcitonin, calcitonin gene-related peptide and adrenomedullin. Using an in vitro model for bacterial infection, we tested the hypothesis that intracellular calcium concentration ([Ca2+]i) is elevated after lipopolysaccharide (LPS) stimulation and is responsible for the LPS-mediated increase in CALC gene expression and protein secretion. In our human adipocyte model, LPS did not show any cytotoxic effects and induced increased CALC-I gene mRNA expression. Additionally, LPS provoked an elevation in [Ca2+]i. The LPS-induced increase in CALC-I gene mRNA was partially blocked with verapamil, an L-type calcium channel blocker and blocked almost completely with 2-aminoethoxydiphenyl borate, a blocker of store-operated calcium entry and inositol triphosphate-mediated calcium release. Treatment of cells with substances elevating [Ca2+] i led to an increased CALC-I mRNA expression level. The combination of LPS with substances raising [Ca2+]i even potentiated this increase. At the same time, elevated [Ca2+]i attenuated the expression level of the CALC-V gene. These findings indicate that, in human adipocytes, changes in [Ca2+]i are involved in LPSregulated expression of CALC genes, thereby strengthening previous findings postulating a crucial role of intracellular calcium homeostasis in the state of bacterial infection and sepsis.

The mechanisms of metformin effects on glucose transport and metabolism were investigated in human adipocytes. Human preadipocytes obtained from surgical biopsies were differentiated in vitro into adipocytes and the effects of metformin on glucose uptake, glucose oxidation and the involved signaling pathways were analyzed. Metformin (1mM, 24h) increased glucose uptake 2.3±0.2-fold (p

Exercise increases muscle derived Interleukin–6 (IL–6) leading to insulin secretion via glucagon-like peptide–1. IL–1 antagonism improves glycemia and decreases systemic inflammation including IL–6 in patients with type 2 diabetes. However, it is not known whether physiological, exercise-induced muscle-derived IL–6 is also regulated by the IL–1 system. Therefore we conducted a double blind, crossover study in 17 healthy male subjects randomized to receive either the IL–1 receptor antagonist IL-1Ra (anakinra) or placebo prior to an acute treadmill exercise. Muscle activity led to a 2–3 fold increase in serum IL–6 concentrations but anakinra had no effect on this exercise-induced IL–6. Furthermore, the IL–1 responsive inflammatory markers CRP, cortisol and MCP–1 remained largely unaffected by exercise and anakinra. We conclude that the beneficial effect of muscle-induced IL–6 is not meaningfully affected by IL–1 antagonism. Trial Registration ClinicalTrials.gov NCT01771445

Aims The role of the IL-1 system in development of type 2 diabetes is well established. Using an IL-1 receptor antagonist, which blocks IL-1alpha and -beta activity, or by specifically neutralizing IL-1beta, several clinical studies have demonstrated improvement in insulin secretion and glycaemia. However, the role of IL-1alpha remains to be investigated. Methods We evaluated the safety and preliminary efficacy of a neutralizing true human™ monoclonal antibody against IL-1alpha (MABp1) in an open label trial in patients with type 2 diabetes. Seven patients between 50 to 66 years with type 2 diabetes mellitus were enrolled in the study. The study subjects received four biweekly intravenous infusions of MABp1 at 1.25 mg/kg body weight up to day 60 and were followed up for a total of 90 days. Results Compared to baseline, after the 60-day period of treatment HbA1c was numerically reduced by 0.14 ± 0.21% (p = 0.15), fasting C-peptide was increased by 88% (p = 0.03), pro-insulin by 48% (p = 0.03) and insulin numerically increased by 74% (p = 0.11). Systolic blood pressure numerically decreased by 11 mmHg (p = 0.2). Both HbA1c and blood pressure rebounded to baseline levels thirty days after the end of MABp1 application. Treatment with MABp1 was well tolerated, and no adverse events occurred during the study. Conclusion The results point to a role of IL-1alpha in type 2 diabetes and encourage further investigations. (ClinicalTrials.gov number NCT01427699).

Context: The polyuria-polydipsia syndrome comprises primary polydipsia (PP) and central and nephrogenic diabetes insipidus (DI). Correctly discriminating these entities is mandatory, given that inadequate treatment causes serious complications. The diagnostic “gold standard” is the water deprivation test with assessment of arginine vasopressin (AVP) activity. However, test interpretation and AVP measurement are challenging. Objective: The objective was to evaluate the accuracy of copeptin, a stable peptide stoichiometrically cosecreted with AVP, in the differential diagnosis of polyuria-polydipsia syndrome. Design, Setting, and Patients: This was a prospective multicenter observational cohort study from four Swiss or German tertiary referral centers of adults >18 years old with the history of polyuria and polydipsia. Measurements: A standardized combined water deprivation/3% saline infusion test was performed and terminated when serum sodium exceeded 147 mmol/L. Circulating copeptin and AVP levels were measured regularly throughout the test. Final diagnosis was based on the water deprivation/saline infusion test results, clinical information, and the treatment response. Results: Fifty-five patients were enrolled (11 with complete central DI, 16 with partial central DI, 18 with PP, and 10 with nephrogenic DI). Without prior thirsting, a single baseline copeptin level >21.4 pmol/L differentiated nephrogenic DI from other etiologies with a 100% sensitivity and specificity, rendering a water deprivation testing unnecessary in such cases. A stimulated copeptin >4.9 pmol/L (at sodium levels >147 mmol/L) differentiated between patients with PP and patients with partial central DI with a 94.0% specificity and a 94.4% sensitivity. A stimulated AVP >1.8 pg/mL differentiated between the same categories with a 93.0% specificity and a 83.0% sensitivity. Limitation: This study was limited by incorporation bias from including AVP levels as a diagnostic criterion. Conclusion: Copeptin is a promising new tool in the differential diagnosis of the polyuria-polydipsia syndrome, and a valid surrogate marker for AVP. Primary Funding Sources: Swiss National Science Foundation, University of Basel.

Mesenchymal stem cells (MSC) from mouse bone marrow were shown to adopt a pancreatic endocrine phenotype in vitro and to reverse diabetes in an animal model. MSC from human bone marrow and adipose tissue represent very similar cell populations with comparable phenotypes. Adipose tissue is abundant and easily accessible and could thus also harbor cells with the potential to differentiate in insulin producing cells. We isolated human adipose tissue-derived MSC from four healthy donors. During the proliferation period, the cells expressed the stem cell markers nestin, ABCG2, SCF, Thy-1 as well as the pancreatic endocrine transcription factor Isl-1. The cells were induced to differentiate into a pancreatic endocrine phenotype by defined culture conditions within 3 days. Using quantitative PCR a down-regulation of ABCG2 and up-regulation of pancreatic developmental transcription factors Isl-1, Ipf-1, and Ngn3 were observed together with induction of the islet hormones insulin, glucagon, and somatostatin.

Contracting muscle releases interleukin-6 (IL-6) enabling the metabolic switch from carbohydrate to fat utilization. Similarly, metabolism is switched during transition from fed to fasting state. Herein, we examined a putative role for IL-6 in the metabolic adaptation to normal fasting. In lean C57BL/6J mice, 6 h of food withdrawal increased gene transcription levels of IL-6 in skeletal muscle but not in white adipose tissue. Concomitantly, circulating IL-6 and free fatty acid (FFA) levels were significantly increased, whereas respiratory quotient (RQ) was reduced in 6-h fasted mice. In white adipose tissue, phosphorylation of hormone-sensitive lipase (HSL) was increased on fasting, indicating increased lipolysis. Intriguingly, fasting-induced increase in circulating IL-6 levels and parallel rise in FFA concentration were absent in obese and glucose-intolerant mice. A causative role for IL-6 in the physiological adaptation to fasting was further supported by the fact that fasting-induced increase in circulating FFA levels was significantly blunted in lean IL-6 knockout (KO) and lean C57BL/6J mice treated with neutralizing IL-6 antibody. Consistently, phosphorylation of HSL was significantly reduced in adipose tissue of IL-6-depleted mice. Hence, our findings suggest a novel role for IL-6 in energy supply during early fasting.

Objective: To study the effects of metformin on lipolysis and hormone sensitive lipase (HSL) phosphorylation in human adipocytes treated with lipolytic and inflammatory agents. Methods: Lipolysis and phosphorylation status of HSL were assessed in subcutaneous pre adipocytes surgically isolated from patients and differentiated into mature adipocytes in vitro. Results: Stimulation for 1?h with forskolin isoproterenol and IBMX or stimulation for 24?h with LPS IL 1ß and TNF a increased lipolysis (p?0.05 vs. basal). The phosphorylation of HSL at Ser 554 was decreased while the Ser 552 phosphorylation was increased. Pre incubation with metformin (24?h 1?mM) inhibited forskolin isoproterenol IBMX LPS IL 1ß and TNF a induced glycerol release and prevented p(Ser554)HSL decrease and p(Ser 552)HSL increase due to lipolytic and inflammatory agents. AMPKa1 is involved in metformin induced HSL phosphorylation at Ser 552. Conclusion: Phosphorylation of HSL at Ser 554 inversely correlates with lipolysis and HSL phosphorylation at Ser552 in human adipocytes.

Context: Increased plasma levels of glucose-dependent insulinotropic polypeptide (GIP), calcitonin CT gene-related peptide (CGRP)-I, and procalcitonin (Pro-CT) are associated with obesity. Adipocytes express functional GIP receptors and the CT peptides Pro-CT and CGRP-I. However, a link between GIP and CT peptides has not been studied yet. Objective: The objective of the study was the assessment of the GIP effect on the expression and secretion of CGRP-I and Pro-CT in human adipocytes, CGRP-I and CT gene expression in adipose tissue (AT) from obese vs. lean subjects, and plasma levels of CGRP-I and Pro-CT after a high-fat meal in obese patients. Design and Participants: Human preadipocyte-derived adipocytes, differentiated in vitro, were treated with GIP. mRNA expression and protein secretion of CGRP-I and Pro-CT were measured. Human CGRP-I and CT mRNA expression in AT and CGRP-I and Pro-CT plasma concentrations were assessed. Results: Treatment with 1 nm GIP induced CGRP-I mRNA expression 6.9 ± 1.0-fold (P < 0.001 vs. control) after 2 h and CT gene expression 14.0 ± 1.7-fold (P < 0.001 vs. control) after 6 h. GIP stimulated CGRP-I secretion 1.7 ± 0.2-fold (P < 0.05 vs. control) after 1 h. In AT samples of obese subjects, CGRP-I mRNA expression was higher in sc AT (P < 0.05 vs. lean subjects), whereas CT expression was higher in visceral AT (P < 0.05 vs. lean subjects). CGRP-I plasma levels increased after a high-fat meal in obese patients. Conclusion: GIP induces CGRP-I and CT expression in human adipocytes. Therefore, elevated Pro-CT and CGRP-I levels in obesity might result from GIP-induced Pro-CT and CGRP-I release in AT and might be triggered by a high-fat diet. How these findings relate to the metabolic complications of obesity warrants further investigations.

High fat diet-induced endotoxaemia triggers low-grade inflammation and lipid release from adipose tissue. This study aims to unravel the cellular mechanisms leading to the lipopolysaccharide (LPS) effects in human adipocytes. Subcutaneous pre-adipocytes surgically isolated from patients were differentiated into mature adipocytes in vitro. Lipolysis was assessed by measurement of glycerol release and mRNA expression of pro-inflammatory cytokines were evaluated by real-time PCR. Treatment with LPS for 24 h induced a dose-dependent increase in interleukin (IL)-6 and IL-8 mRNA expression. At 1 µg/ml LPS, IL-6 and IL-8 were induced to 19.5 ± 1.8-fold and 662.7 ± 91.5-fold ( P

To evaluate the effect of metformin on basal and insulin-induced glucose uptake in subcutaneous and visceral preadipocyte-derived adipocytes from obese and non-obese patients, preadipocytes were obtained from subcutaneous and visceral fat depots during abdominal surgery. Differentiation efficiency was evaluated by measurement of intracellular triglyceride accumulation. Preadipocyte-derived adipocytes were treated with metformin (1 mM) for 24 h with or without the addition of insulin (100 nM) for 20 min and glucose uptake was measured. In cells from each donor, intracellular triglyceride accumulation was more abundant in subcutaneous preadipocyte-derived adipocytes than in visceral preadipocyte-derived adipocytes (p < 0.001). Insulin stimulated glucose uptake in subcutaneous preadipocyte-derived adipocytes from both non-obese and obese patients (p < 0.001 vs. basal). In visceral preadipocyte-derived adipocytes, insulin did not increase basal glucose uptake. In subcutaneous preadipocyte-derived adipocytes from non-obese and obese patients, metformin alone increased glucose uptake to 2.7 +/- 0.2 (p < 0.001) and 2.1 +/- 0.1 fold (p < 0.001) respectively. Metformin increased glucose uptake in visceral preadipocyte-derived adipocytes from non-obese (1.7 +/- 0.1 fold vs. basal, p < 0.001) and obese (2.0 +/- 0.2 fold vs. basal, p < 0.001) patients. Combined treatment with metformin and insulin increased glucose uptake in subcutaneous preadipocyte-derived adipocytes from both non-obese and obese patients (p < 0.001 vs. insulin alone). In preadipocyte-derived adipocytes glucose uptake is induced by metformin independent of the fat depot origin of the preadipocytes (subcutaneous or visceral) and the obesity state of the patients (non-obese or obese). In adipocytes, metformin seems to induce glucose uptake independent of insulin suggesting an alternative mechanism of action of this drug.

Inhibition of tumor necrosis factor (TNF)-α is an effective treatment for Crohn disease. It is recommended as a second-line therapy in steroid-dependent or -refractory disease, although first-line treatment may improve chances of intestinal mucosal healing (1). In the context of diabetes, TNF-α has been implicated in the development of insulin resistance during obesity (2) and in autoimmune destruction of pancreatic β-cells in an animal model of type 1 diabetes (3), and a recent study demonstrated some preservation of insulin secretion in children with new-onset type 1 diabetes upon TNF-α inhibition (4). Here, we report a case of a 29-year-old Caucasian man who was diagnosed with type 1 diabetes at the age of 27 years on the basis of rapid onset of hyperglycemia, a lean BMI of 22.7 kg/m2, signs of β-cell autoimmunity (autoantibodies to GAD 476 IU/mL [normal value